What's wrong with that? I repeat, Wikipedia should let *anyone* edit. Just because someone uses AOL doesn't mean s/he should have to register and create an account to edit. We're "forcing" users, to quote from you, to register when the whole point of Wikipedia is that you don't need to register to edit.
I really can't figure out what you're arguing here, though. Because right now, when an AOL IP is blocked, you can't edit using it regardless of whether or not you register. As I understand it, the proposal is to allow logged in users to edit when they otherwise wouldn't. Sure, this might lead to admins being more liberal with IP blocks, but it doesn't require it - whether or not admins are more liberal with IP blocks is a separate issue, and we could pass policies to ensure that this doesn't happen.